The present invention relates to the technical area of self-stripping connecting devices for connecting sheathed electrical conductors.
It is known that a sheathed electrical conductor can be connected for example with an element belonging to a terminal block with the aid of a self-stripping connection. The device allowing this self-stripping connection has an electrically conducting jaw with a slot whose width substantially corresponds to the diameter of the electrical conductor and whose sharp edges are designed to cut the insulating sheath when the conductor is inserted into the stirrup along the axis of the slot in order to provide electrical contact between the conductor and the stirrup. The stirrup is mounted in an insulating support which itself has a slot aligned with the slot of the stirrup and which ensures passage of the conductor and gripping of the latter. If the jaw holds the conductor, the holding and mechanical strength are improved by the gripping of the insulating sheath in a slot provided in the insulating support.
This configuration confers very good vibration resistance and tensile strength on the conductor along its axis. However, when the conductor is pulled in the direction of the slot, with cables having an insulating sheath of a particular type, the conductor cable may break.
The goal of the invention is to provide a self-stripping connecting device for a sheathed electrical conductor of the aforementioned type in which the breaking strength of the conductor in the direction of the slot is improved.
For this purpose, the self-stripping connecting device for connecting at least one electrical cable has a conducting core surrounded by an insulating sheath of the type having:
an interconnecting part provided with at least one stripping and connecting jaw formed by a tubular body that, in one face, has a stripping and holding slot designed to cut the insulating sheath down to the conducting core, for connecting and holding the conducting core,
and an insulating housing defining at least one connecting chamber which contains the stripping jaw and which has, in a wall located opposite the stripping slot, a gripping slot designed to pinch the insulating sheath of the cable,
According to the invention, the connecting device is characterized in that the gripping slot is at least partially offset laterally from the stripping slot.
Depending on the degree of holding force desired, it is possible to implement these various configurations either individually or in various possible combinations.
According to one feature of the invention, the axis of the gripping slot is parallel to the axis of the stripping jaw and offset laterally with respect thereto. Thus, the conductor follows a path from the inside of the stirrup to the outside of the insulating support that is not a straight line but is in the shape of a very open S, which is favorable to holding of the cable and increases the tensile strength of the connection provided by the device according to the invention.
According to another feature of the invention, the gripping slot is inclined and its inclination is such that the area of the gripping slot serving for passage of the conductor, in the connecting position, is offset laterally relative to the area of the stripping slot receiving the conductor in this same connecting position. Once again, the purpose is to confer on the conductor a shape that is non-rectilinear to increase its breaking strength.
According to another feature of the invention, the gripping slot has a local pinch which is preferably but not necessarily located in the vicinity of the end of the slot used for inserting the conductor.
This local pinch in the gripping slot then impedes breakage of the connected cable in the direction of the slot.
Advantageously, the width of the gripping slot in the pinch area is less than its width over the rest of its length.
To improve the breaking strength in the direction of the slot still further, the pinch of the slot provided in the insulating support is offset laterally relative to the axis of the slot in the rest of its length to create a type of baffle.
According to a first option, the local pinch in the slot provided in the insulating support is achieved by forming the insulating support when it is cast.
According to another option, the local pinch in the slot provided in the insulating support is obtained by attaching a part made independently of the support, to the support.
According to the invention, the electrical cable is held in position by the pinching of the conducting core at the slot of the stripping jaw and by pressure applied to the insulating sheath surrounding the cable conducting core at the gripping slot of the insulating housing. These two effects, pinching and gripping, are further accentuated by the at least partially offset configuration of the stripping and gripping slots.
Another goal of the invention is to improve the holding of the connected cable by the gripping slot in the insulating housing.
Thus, according to another feature of the invention, the gripping slot is delimited by two wall elements of the housing, a first element of which, called the supporting element, is thicker than the second element, called the gripping element. Preferably but not strictly necessarily, the supporting element defines the edge of the gripping slot that is located nearest to an axial plane of symmetry of the stripping slot.
According to another preferred feature of the invention, the gripping element is elastically deformable and is less rigid than the supporting element. Thus, the gripping element applies the cable engaged in the gripping slot against the supporting element.
According to another feature of the invention, the gripping element increases in rigidity with distance from the insertion end of the gripping slot. Thus, the gripping element is shaped so that its maximum rigidity is in a region located opposite to the insertion end of the gripping slot and is designed to receive the electrical cable in the connected position.
According to another feature of the invention, the gripping element is integral with a lateral wall in the insulating housing. Preferably but not strictly necessarily, the part of the lateral wall bearing the gripping element has a concave outer face intended to favor elastic deformation of the gripping element and the wall bearing it when the sheathed conductor passes through.
According to a preferred feature, the part of the lateral wall bearing the gripping element is shaped so that it can deform when the cable to be connected is inserted, without increasing the nominal thickness of the insulating housing during this insertion phase.
When several devices according to the invention disposed side by side are used, this advantageous feature of the invention prevents any disorder in juxtaposition when the conductors to be connected are put in place. Since the lateral wall deforms when the conductor passes through, while remaining within the nominal dimensions of the housing, it places no stress on the adjacent housing whose positioning is thus not impeded by the connecting of the electrical cable.
According to another feature of the invention, to prevent the connected cable from being unintentionally extracted, the supporting element, at the insertion end of the gripping slot, has a projecting element defining a local pinch in the gripping slot.
According to another feature of the invention, to facilitate insertion of the cable to be connected, the part of the wall of the housing bearing the gripping element and located opposite the projecting element has a reduced thickness.
Similarly, and according to another feature of the invention, the inner face of the lateral wall of the housing bearing the gripping element has a concave area located opposite a projecting element.
According to another feature of the invention, the gripping element has a reinforcement opposite the projecting element.
According to another feature, the body of the jaw has an essentially C-shaped cross section.
According to a preferred feature of the invention, the body of the jaw has an essentially polygonal cross section having a core from which extend two essentially parallel branches each of which has an arm opposite the core, the ends of which arm define the edges of the stripping slot. Preferably, the arms converge toward each other and opposite the core of the body of the stripping jaw. This feature of the invention increases the effectiveness of the stripping jaw particularly in its electrical cable holding and maintenance function.